“Simple illnesses like gastroenteritis, and respiratory problems like chest infections are a bit more frequent after school starts, simply because children have been sharing their bugs with a very small population over the summer holidays, and at school there are loads of susceptible friends to catch them.

“The only way to protect children is through general healthy-living measures.

“Take general, sensible measures like washing hands when you’ve been to the toilet or sneezed - nothing new, just common sense.”

Most of the time, these illnesses are minor, but if you are concerned, get medical advice.

Dr Hesseling adds: “Parents know their children best, and if they feel there’s something seriously wrong they need to get them seen, sooner rather than later, instead of thinking it’s just because they’re back at school.”

COLDS AND FLU: Kids are more prone than adults - it’s estimated they get eight or more a year. But aside from soothing the symptoms, there’s not an awful lot parents can do. Flu can make kids quite poorly, but it usually isn’t serious unless there are complications, or a child has pre-existing health problems.

“There are obviously cases where flu can become a real problem, for example, in immunocompromised children, but generally healthy children can fight the illness off without major support - mostly parental TLC, a bit of paracetamol, plus plenty of fluids,” says Dr Hesseling.

GASTROENTERITIS: Tummy bugs (gastroenteritis), caused by viral or bacterial infections, are another common term-time affliction. The most common cause in children is a virus called rotavirus, which can be transferred to food, objects and surfaces if infected children don’t wash their hands after going to the toilet.

Usually, it’s not serious, but it’s important to ensure your child doesn’t become dehydrated by giving them plenty of fluids. If symptoms are severe and your child seems very unwell and dehydrated, or if vomiting continues for more than three days - or diarrhoea for more than a week - consult a doctor.

CHICKEN POX: It starts with children feeling unwell, a slight temperature and a rash, which turns into itchy spots and then fluid-filled blisters which eventually dry into scabs. Treatment is simply giving children plenty of fluids, paracetamol or ibuprofen to relieve fever and discomfort, baths, dressing them in loose comfortable clothes, and calamine lotion to help ease itching. This can cause complications in pregnant women, so it’s important to isolate children until they’re not infectious any more (when the blisters scab over).

And while there’s no way of avoiding infections all together, Dr Hesseling says it’s worth giving your child’s immune system a helping hand, by encouraging them to eat a healthy, balanced diet with lots of fruit and vegetables, and to make sure they have plenty of exercise.

Leeds-based charity Heart Research UK has compiled its top tips to create healthy, fun lunches which youngsters will love.

First let them choose their own lunch box or bag, and plan so you’ve time to make lunch the night before.

Alternate different types of bread and choose healthy fillings such as lean meat, chicken, fish, hummus and low fat cheese. And for a change, try rice, pasta or couscous made with colourful, finely chopped vegetables and add fish, chicken or beans and pulses for protein.

Ensure you include plenty of fruit and veg, as well as drink such as water to keep them hydrated and aid concentration.